Dental x-ray package



. June 16, 1942. F. c. MARTIN 2,286,748

DENTAL X-RAY PACKAQE Filed OGL' 26, 1940 FIG].

FREDERICK cmRTIN INVENTOR- ATTORNEY Patented June 16, 1942 DENTAL X-RAYPACKAGE Frederick C. Martin, Rochester, N. Y., assignor to Eastman KodakCompany, Rochester, N. Y., a corporation of New Jersey ApplicationOctober 26, 1940, SerialNo. 363,049

3 Claims.

This invention relates to an improvement in dental X-ray film packages.These are made by the manufacturer with one or two pieces of sensitivefilm in a small sealed envelope or flat package ready to be placed inthe mouth of a patient for exposure to X-rays. They ordinarily contain athin sheet of metal foil of the same size as the film and the packagescarry some exterior indi cation so that when used, the metal foil willbe on the side away from the X-ray instrument.

To assist the operator in correctly positioning the package, the filmsometimes carries a protuberance and the outer surface of the packagecarries an indication as disclosed in my prior Patent 1,748,490, grantedFebruary 25, 1930. ever, the package is inadvertently placed in thepatients mouth with the foil side facing the source of X-rays and a fullexposure made, an image of the teeth will be formed in the sensitivefilm since the foil is thin and passes an appreciable percentage of therays. When the diagnostician inspects the film, he will see theprotuberance and assume that the exposure was correctly made andnaturally will think it represents the side of the jaw opposite to theone exposed. Instances have occurred where, under these circumstances,the wrong tooth was extracted. This error in positioning the package hasnot been readily detectible from the film since the foil is of uniformthickness, and, if the image is thin, this may be attributed toinsufficient exposure or development, or'to develop ment in cold orexhausted solutions.

The object of my invention is to provide a means positively detectingsuch an error from the developed film, and this I do by forming in thefoil apertures or thin places, preferably in the form of a recognizablecharacter or design, or by otherwise forming on the reverse side of thepackage, characters having different impermeability to X-rays than therest of the package.

Reference will now be made to the accompanying drawing wherein Fig. 1 isa cross-section of a typical dental X-ray package shown by way ofexample.

Fig. 2 is a similar section of a differently constructed package.

Fig. 3 is a plan view of a sheet of metal foil used in the package.

Fig. 4 is a plan of an exposed and developed,

but incorrectly positioned, film.

Fig. 5 is a section of a package embodying still a different embodimentof my invention.

It is to be understood that my invention is applicable to any of themany known dental X-ray If, howfilm packages now on the market andhaving a sheet of metal foil on one side of'the film. A typical packageis shown in Fig. 1, wherein the film comprises a support S with asensitive emulsion E upon each surface. Since identical registeringimages are formed in each emulsion, it cannot betold from an inspectionof the images,

which surface actually faced the film. Even though a protuberance P isformed on the film, as described in my patent mentioned above, thismerely indicates which surface should have faced the X-rays and doesnot' assure that it was actually correctly positioned. A sheet of metalfoil M is located on one side of the .film. An opaque paper sheet D ofthe same size as the foil and film is placed outside the foil and. thepackage is closed with an opaque pa'per wrapper W covering the othersurface with its borders B folded over and adhesively secured to thesheet D.

A different package is shown in Fig. 2, wherein two films, each having asupport S and a single emulsion layer E, are packed with their emulsionsurfaces facing away from the sheet of metal foil M which is placed onone side of these, a sheet of paper 0' being on the other side. Awrapper W is placed over the foil and its borders B adhesively securedto the sheet 0.

There is formed in the sheet of foil a character X, which, in Fig. l, isshown as a thinned area, and in Fig. 2 as a perforation X' in the metalfoil.

The packages are intended to be exposed from the side indicated by thearrow in Figs. 1 and 2, and this is known to the operator by indicia. ordirections on the package or by reason of the structure of the package.When so exposed, the film, when developed, will carry the images of theteeth without obstruction. If, however, the exposure is made through thesheet of metal foil, there will be impressed in the sensitive layer, alatent image of the character which will become strikingly visible atthe first inspection after development, as shown in Fig. 4 where thedeveloped character is shown as .73.

One of the purposes of the metal foil is to prevent secondary radiationfrom the body tissue reaching and affecting the film. We have found thatsmall apertures or thinned areas do not cause a discernible effect uponthe image because of possible differences in secondary radiation. Inpractice, the foil is made of tin or lead having a thickness of theorder of .003 inch, the thin area being half as thick. These may bereadily made by passing the foil in a strip, before being cut to size,under a roller with embossing characters on its periphery.

Still another embodiment of my invention is shown in Fig. 5, wherein thepackage is identical with that shown in Fig. 1, except that instead offorming an aperture or thin area in the foil, an additional character X"of lead or other heavy metal is added, thus giving a light, instead of aheavy, image in the developed film. This form of the invention isparticularly applicable to a package not containing a sheet of metalfoil.

Since a fihn exposed from the wrong side gives a mirror image of thatobtained when correctly exposed, (that is, an image reversed from leftto right) it is possible with an ordinary film to mistake an exposure ofone side of the jaw for one of the other side. If, however, the packageembodies my invention and, moreover, the film has a protuberance Pindicating which side should have faced the X-rays, the developed filmwill positively show which side should have faced the X-rays and whichside actually did; and the diagnostician, in examining the film, haspositive assurance upon which he can rely with confidence, as to theexposure having been correctly made and as to which side of the jaw wasexposed.

It is to be understood that the indication on the exterior of thepackage as to which side should face the X-rays may be a printeddirection, a symbol or character, or merely the structure of the packagewhere the accompanying directions inform the operator as to its properuse.

It is to be understood that the structures described are by way ofexamiple and that I contemplate numerous modifications and equivalents,within the scope of the appended claims, as included within myinvention.

I claim:

1. As an article of manufacture, a light-tight dental X-ray film packagecontaining a sensitized film, and means on the exterior of the pack ageindicating which side thereof should face a source of X-rays, saidpackage including in its structure on the side thereof intended to faceaway from the source of X-rays areas having distinctly differentpermeability to X-rays, whereby if the package is exposed to X-rays fromthe reverse side, a latent image of such areas will be formed in thesensitive film.

2. As an article of manufacture, a dental X-ray film package comprisinga sheet of film with a sensitive emulsion upon each surface thereof andhaving an identifiable means indicating which side thereof should face asource of X-rays and a light-tight enclosure therefor, said enclosurecarrying on the exterior thereof means indicating which side of thepackage should face a source of X-rays and means on the side thereofintended to face away from the source of X-rays having areas ofdistinctly dif ferent permeability to X-rays, whereby if the package isexposed to X-rays from the side opposite that indicated by the film andthe enclosure, a latent image of such areas will be formed in thesensitive film.

3. As an article of manufacture, a light-tight dental X-ray packageincluding a sheet of film with a sensitive emulsion upon each surfacethereof and having an identifiable means indicating which side thereofshould have faced a source of X-rays and a sheet of metal foil upon oneside of said sheet of film and coextensive therewith, there being in thefoil an area of characteristic shape transmitting X-rays more freelythan the rest of the sheet of foil.

FREDERICK C. MARTIN.

